#include<bits/stdc++.h>
using namespace std;
int main(){
	int n,first[10005],second[10005];
	double max = 0.0;
	cin >> n;
	for(int i = 0;i < n;i++){
		cin >> first[i] >> second[i];
		double temp = sqrt(first[i]*first[i]+second[i]*second[i]);
		if(temp>max) max = temp;
	}
	printf("%.2f",max);
	return 0;
}

